This invention relates to an illumination system for illuminating surface of various kinds of device with colored lights. The lights are cast from the inside of the device to the surface to project an image such as an emblem, symbol, trademark and geometrical pattern on the surface. Particularly, the illumination system is suitably incorporated with a portable electronic device.
Recently, some of portable electronic devices such as a portable telephone terminal, PDA (personal data assistant) and wrist watch have a illumination system for emitting various color lights in response to a predetermined action of the devices.
For example, a illumination system of a portable telephone terminal project an emblem on the surface of the portable telephone terminal when the terminal receives a call, or during the terminal is establishing a connection with another telephone terminal.
A portable telephone terminal 101 shown in FIG. 1 has a foldable housing 102 and is now folded in FIG. 1. On an upper housing 103, an conventional illuminator 104, an auxiliary display device 105 and an antenna 106 is installed. The illuminator 104 emits light to Indicate an arrival of a call or establishment of a connection with another telephone terminal. The sub display device 105 displays information when the foldable housing 102 is folded. The antenna 106 directs incoming and outgoing radio waves.
As shown in FIG. 2, the illuminator 104 includes a light source unit 107 and a screen 108. As shown in FIG. 3, the light source unit 107 includes a red LED 107r, a green LED 107g and a blue LED 107b on a print-circuit plate Lights emitted from the LEDs are cast on the screen 108.
The LEDs blink according to a predetermined blinking pattern in order to cast a single one or a mixture of two or three colors on the screen 109. For example, if the blinking pattern consists of combinations of ON/OFF of the LEDs, then the screen 108 is colored in one of red, green, blue, yellow, cyan, magenta, white and black.
Whichever a single LED or plural LEDs emit, a single color is cast on the screen 108 at one time as shown in FIG. 4. Therefore, the screen 108 cannot be divided into plural areas each of which has a different color from each other. Consequently, it is unable to express on the screen 108 that an object with a color moves on a background with another color.
Related arts are disclosed on Japanese Patent Publication No. 2001-166738, in which a group of LEDs including a red, green and blue LEDs